Lift having self-folding platform

ABSTRACT

A lift which contains a self-folding platform is disclosed. The rear of a truck may be equipped with the lift to provide a loading and unloading device as well as a tailgate for the truck.

llnite Erlincler tates Patent [191 Aug. 27, 1974 1 1 LEFT HAVllNGSELF-FOLDlNG PLATFORM [76] Inventor: Atwood E. Erlinder, 12221 S.

Indiana Ave, Palos Heights, 111. 60628 [22] Filed: Apr. 27, 1972 [21]Appl, No; 248,327

Related US. Application Data [62] Division of Ser. No. 53,872, July 10,1970, Pat. No.

[52] US. Cl 214/75 T, 187/9, 214/77 P [51] 1111. C11. 1160p 1/44 [58]lField of Search 214/75 T, 75 R, 77 P, 85; 187/9, 95; 14/71, 72

[56] References Cited UNITED STATES PATENTS Satsky 2174/75 T 2,706,5654/1955 Krasno 214/75 T 2,718,431 9/1955 Pietroroia.... 214/85 2,727,78112/1955 DEath 214/85 2,792,079 5/1957 Gibson 187/9 3,520,426 7/1970Hostetler 214/75 T Primary Examiner-Robert J. Spar AssistantExaminer-Lawrence J. Oresky Atlorney, Agent, or Firm-Merriam, Marshall,Shapiro & Klose A lift which contains a self-folding platform isdisclosed. The rear of a truck may be equipped with the lift to providea loading and unloading device as well as a tailgate for the truck.

11 filaims, 14 Drawing Figures sum 30; 3

LIFT HAVING SELF-FOLDING PLATFORM This is a division of application Ser.No. 53,872, filed July 10, 1970, now US. Pat. No. 3,675,739, whichissued July ll, 1972.

The present invention concerns an improved lift. In general, it relatesto a lift having a foldable platform. More particularly, it concernsalift which contains a foldable platform and means for folding andunfolding the platform. In a preferred embodiment of the presentinvention. the rear of a truck is equipped with the lift to provide aversatile device for loading and unloading the trucks cargo as well asto provide a tailgate for the truck.

In many instances where lifts of the horizontal platform type areemployed, it is desirable that the plat form he of a size sufficient toaccomoda te the cargo or freight when the lift isin use, and of adifferent, more compact, configuration when the lift is not in use. Forexample, when a lift of the platform type is employed as a loading andunloading device for a truck, it is desirable to have a horizontalplatform which has a rectangular surface of sufficient size and shape toaccommodate the trucks cargo. Often, the result is a platform which maybe difficult to handle because of size, shape and/or weight. Moreover,such platforms present problems when the lift is being transported, orstored when not in use.

The present invention provides a lift which contains a self-foldingplatform which enables the lift to have a comparatively compactconfiguration when not in use.

The present invention also provides a lift containing a self-foldingplatform which is suitable for use as a device for loading and unloadinga truck and also as a tailgate for the truck.

According to the present invention, there is provided an improved liftwhich contains a self-folding platform. As will be apparent from thedrawings and the following description, the lift of the presentinvention employs chain, cable, or equivalent means to fold and unfold asectioned platform.

A better understanding of the present invention will be had if referenceis made to the accompanying drawings in which:

FIGS. I and 2 are perspective rear views of a truck equipped with aself-folding platform of the present invention; FIG. 1 showing theplatform raised to a height which is level with the bed of the truck andFIG. 2 showing the platform lowered to the ground level;

FIGS. 3 8 inclusive are diagrama'tic side views of a truck equipped witha self-folding lift of the present invention. These figures showdiagramatically the raising, lowering, folding and unfolding of theplatform. FIG. 3 shows the platform completely folded, secured andraised to a position to enable it to function as a tailgate. FIG. 4shows the platform substantially completely folded and lowered to alevel below the level of the truck-bed. FIG. 5 shows the platformunfolding. FIG. 6 shows the platform substantially unfolded. FIG. 7shows the platform completely unfolded and raised to a height which islevel with the bed of the truck. FIG. 8 shows the platform completelyunfolded and lowered to substantially ground level;

FIG. 9 is a fragmentary section taken along a line 9-9 in FIG. 3;

FIG. 10 is a fragmentary perspective view of the dual channel tracksemployed in the lift of the present invention;

FIGS. I2 and 13 are diagramatic side views of an embodiment of thepresent invention wherein a selffolding platform lift is mounted on acollapsible frame provided with casters;

FIG. I4 is a perspective rear view of a sclffolding platform lift ofthepresent invention mounted to a wall, said lift employing a cable to foldand unfold the platform.

FIGS. l and 2 show a truck I equipped with a lift 2 of the presentinvention. The lift 2 generally comprises a foldable hinged platform 3,a pair of dual channel tracks 8, a pair of dead chains 6, a pairofchains 7, and a lift mechanism 10.

The foldable hinged-platform 3 comprises a first platform section 4 anda second platform section 5 which are joined together by hinge 9. Eachend of platform section 5 is provided with a locking pin 11. The pair oflocking pins 11 are adapted to removably engage a link of dead chain 6.Platform section 4- is further provided with a pair of chain connectorsl6. Connectors 116 are adapted to connect a link of chain 7 to platformsection 4i. Platform section 4 is preferably, but not necessarily,provided with a beveled edge 17 on the outside of the section 4 tofacilitate the loading and unloading of the platform 3. Platform section4 is also preferably, but not necessarily, further provided with agroove 18 de signed to help facilitate securing rolling cargo to theplatform 3.

Each dual channel track 8 is mounted at the rear of truck l. A box-likechannel 19 of each track 8 provides a passageway and guide forextendable leg 14. The lower extremity of each extendable leg 14 isconnected by pivot connector 15 to platform section 5 so that platformsection 5 will move up or down, respectively,

as extendable legs 14 are retracted or extended with re spect to channel19. The upper extremity of each extendable leg 14 is provided with aflange connector 13 which provides a means for securing ends of chains 7to legs lid so that the chains 7 will move up or down respectively, whenlegs M are retracted or extended. Each track 8 is further provided withgenerally U- shaped channel 21. Channels 21 function as guides forlocking pins Ill when platform section 5 is locked into tracks 8.

Lift mechanism provides the power necessary to operate (i.e., raise,lower, fold, unfold) lift 2. Lift mechanisms are known in the prior artand, per se, form no part of the present invention. A suitable liftmechanism may comprise an electrically powered hydraulic unit (not fullyshown) which includes a system of pulleys and cables (not shown) whichis arranged so that a pair of cable ends may be jointly raised orlowered inresponse to an electric signal generated when the truckdriver, or other lift operator, trips a switch which causes the electricpower supply to activate the hydraulic unit which in turn moves thecable and pulley system to jointly raise or jointly lower the pair ofmovable cable ends (not shown).

The movable pair of cable ends are positioned in boxlike channels 19, sothat one of each said movable cable ends is affixed near, or,preferably, to the top of extendable leg 14. The cable ends may beattached to extendable leg 14 in any suitable manner which does notinterfere with the movement of legs 14 in channels I9.

FIGS. 9, I and 11 show details of the tracks 8 and the unlockingmechanism. Each track 8 is provided with a generally U-shaped channel 21which receives locking pins ll of platform section when platform 3 isurged towards a substantially vertical position. Both U-shaped channels21 are identical and each contains a front flange 22 and a rear flange23. Front flange 22 is shorter in length than rear flange 23. The lowerend of front flange 22 is positioned with respect to tract 8 at avertical height from ground level just sufficient to enable locking pinsIll to clear front flange 22, and therefore disengaged or unlock fromchannel 21 when platform section 5 is in a substantially verticalposition and extendable legs 14 have been extended from track 8 to asubstantially ground level position. FIG. II shows details of thelocking mechanism in both the locked and unlocked positions.

Typical operation of the self-folding platform lift of the presentinvention will now be described.

When the lift is not in use, the foldable hinged platform is in a foldedposition and locked to the tracks, for example as shown in FIG. 3.

When a truck driver or other lift operator desires to operate the lift,the folded lift is first unlocked by the operator tripping a switch toactivate the lift mechanism to lower, i.e., extend, the legs 14 tosubstantially ground level, at which point the locking pins ll clearfront flanges 22 of U-shaped channels 21 causing platform 3 to beunlocked from tracks 8. When the platform 3 becomes unlocked, it pivotsaround to the connectors in the general direction shown by the arrow inFIG. 5, causing the slack in the pair of dead chains 6 to be removed.

To complete the unfolding of the platform 3, the operator of the lifttrips the switch which activates the lift mechanism to retractextendable legs 14 which results in the platform unfolding as shown inFIG. 6. At the point where the platform 3 is completely unfolded, asshown in FIG. 7, the pair of dead chains 6 become slack and the pair ofchains 7 become taut. At this point the operator of the lift removes thedead chains 6 from the ears 12 which disengages the platform 3 from thedead chains 6. The completelyunfolded platform 3 is then in a positionto be raised or lowered by activating the lift mechanism. FIG. 8 showsthe dead chains disengaged and the unfolded lift in a substantiallyground level position.

While the self-folding platform lift of the present invention has beendescribed primarily in conjunction with its mounting on the rear of atruck, it is apparent that the lift will have utility in otherapplications. For example, in FIGS. I2 and 13, the lift of the presentin vention is shown mounted on a collapsible mobile frame 40 whichcontains casters 4]. for moving the lift, for example, from one positionin a building to another. FIG. 12 shows the lift being moved towards aloading dock 50. FIG. 13 shows the lift in a position abutting theloading dock 50. In such an application, the selffolding platform of thepresent invention provides a lift which may become relatively compactand portable. As is apparent from FIGS. 12 and 13, in addition to theplatform of the lift being adapted for folding when not in use, thecollapsible mobile frame 40 may also be readily collapsed and made morecompact when not in use.

FIG. 14 shows still another embodiment of the present invention whereina lift having a self-folding platform is permanently mounted to a wall.The platform can be folded when the lift is not in use, thereby makingavailable additional floor space.

In the embodiment shown in FIG. 14, the folding means employed comprises(instead of a pair of dead chains 6) a single cable 60. One end 60a ofcable 60 is fixed at a point above the platform, and preferably,centered between the ends of the platform. The other end 6012 of cable60 is provided with a hook 61 or other means for selectively engagingcable connector 62 which may comprise, for example, a ring imbedded inthe platform at a point centered between the ends of the platform.

As described above and illustrated in the accompanying drawings, thelift mechanism has been positioned above the tracks of the lift. It isapparent, however, that the lift mechanism could be placed in otherpositions with respect to the tracks by suitable rearrangement of thecable and pulley system; in such a manner the lift could be modified toenable the platform to raise to a height substantially above truck-bedlevel.

It will be apparent to those skilled in the art that variations may bemade in the details of construction without departing from the spiritand scope of this invention as defined in the pending claims.

What is claimed is:

l. In combination with the rear of a truck, a tailgate lift having afolding platform adapted to also function as a tailgate, said liftcomprising;

a lift mechanism;

a hinged platform having an inner platform section with an outer end andan outer platform section with an inner end and said inner and outerends being joined with a hinged connection;

track means for supporting said platform, and

adapted to guide said platform;

carriage means mounted in said track means for vertical motion;

said inner platform section being pivoted at its inner end to saidcarriage means about a horizontal axis;

flexible supporting means connected between said carriage means and saidouter platform for maintaining both said platform sections horizontalduring load lifting and lowering operations and said platform, carriagemeans, and flexible means movable vertically in unison as a rigid lift;

and means for collapsing said platform by providing an upward, verticalfolding force at said hinged connection, so that as the outer end ofsaid inner platform section is raised relative to the inner end of saidinner platform the underside of said outer platform section becomesfaced with the underside of said inner platform section so that whensaid platform is completely folded the two platform sections arevertically extending and parallel to each other.

2. The combination of claim I wherein said track means extend above thebed of the truck and include a vertically extending slot providing forattachment of the flexible support means with the carriage means abovethe hinged platform whereby the flexible support means moves in saidslot during raising and lowering of the platform.

3. The combination of claim 1 wherein said flexible support meanscomprise a pair of chains adapted to extend fromthe associated carriagemeans to the outer platform section.

4. In combination with the rear of a truck, a tailgate lift for loadingcargo onto the truck bed and having a folding platform adapted to alsofunction as a tailgate, said lift comprising:

a lift mechanism including a hydraulic power unit with a drive cylinderat the rear of the truck and extending transversely of the truck;

a folding hinged platform with a cargo support surface having an innerplatform section joined to an outer platform section with a hingedconnection;

track means for supporting said platform and adapted to guide saidplatform;

carriage means mounted in said track means for vertical motion and saidcarriage means being operatively connected with said drive cylinder forselective raising and lowering of the hinged platform;

said inner platform section being pivoted at its inner end to saidcarriage means about a horizontal axis;

flexible support means connected to said carriage means at a point abovesaid platform and extending downward to said hinged platform formaintaining both of said platform sections horizontal during loadlifting and lowering operations;

and means for collapsing said platform by rotating the cargo supportsurface of the inner platform toward the rear of the truck, wherein, asthe outer platform section is folded into the inner platform section theunderside of said outer platform section becomes faced with theunderside of said inner platform section so that when said platform iscompletely folded the two platform sections are vertically extending andparallel to each other.

5. The combination of claim 4 wherein said track means extend verticallyabove and below the bed of the truck and are disposed at each side endof truck and have a channel shaped cross section providing a verticallyextending slot.

6. The combination of claim 4 wherein said inner platform section andsaid outer platform section include abutting portions extending in agenerally vertical direction when the hinged platform is in a horizontalposition, and further, said hinged connection being attached at theunderside of both the inner platform section and the outer platformsection to thereby dispose the abutting portions of each platformsection in a rotation limiting face to face relation when the hingedplatform is in a horizontal load receiving position.

7. The combination of claim 5 wherein said flexible support meanscomprise a pair of chains extending downward from the associatedcarriage means through the vertically extending slot of the adjacenttrack means to support the outer platform.

8. A platform-type lift adapted to be attached to the rear of a truckhaving a deck for carrying cargo and also having a rear portion throughwhich cargo may be loaded and unloaded from the deck, the improvement 6comprising:

a lift mechanism positioned at the rear portion of said truck and havinga hydraulic power unit with a drive cylinder extending transversely ofthe truck;

a foldable hinged platform adapted to receive cargo for loading andunloading from said truck and said hinged platform including both aninner platform section and an outer platform section pivotally connectedby hinged means;

track means fixedly attached to said truck at the transverse sides ofthe rear portion thereof, and adapted to guide said platform in itsvertical movement;

carriage means mounted in said track means for vertical movement thereinand said carriage means being operatively connected through flexibleload transferring means with said drive cylinder for selective raisingand lowering of the hinged platform;

said inner platform section being pivotally connected at its inner endto the carriage means about a horizontal axis;

flexible chain means extending between the vertically movable carriagemeans and the hinged platform for maintaining both of said platformsections horizontal during load lifting and lowering operations;

platform folding means adjacent the hinged means to exert an upwardvertical force thereby providing for collapsing, folding, rotation ofthe platform sections to a generally vertical collapsed position wherebythe underside of the outer platform section becomes faced with theunderside of the inner platform section.

9. The truck lift of claim 8 wherein the platform folding means forcollapsing said platform sections includes a flexible member extendableto at least one stationary point above said platform on the rear of saidtruck, for urging the underside of said outer platform into a portionadjacent the underside of said inner platform section to thereby presentthe outer and inner platform sections in a folded position wherein thetwo platform sections are vertically extending and parallel to eachother.

110. The truck lift of claim 8 wherein said track means extendvertically above and below the bed of the truck and are disposed at eachside end of truck and have a channel shaped cross section providing avertically extending slot.

Ill. The truck lift of claim 9 wherein said inner platform section andsaid outer platform section include abutting portions extending in agenerally vertical direction when the hinged platform is in a horizontalposition, and further, said hinged connection being attached at theunderside of both the inner platform section and the outer platformsection to thereby dispose the abutting portions of each platformsection in a rotation limiting face to face relation when the hingedplatform is in a horizontal load receiving position.

1. In combination with the rear of a truck, a tailgate lift having afolding platform adapted to also function as a tailgate, said liftcomprising; a lift mechanism; a hinged platform having an inner platformsection with an outer end and an outer platform section with an innerend and said inner and outer ends being joined with a hinged connection;track means for supporting said platform, and adapted to guide saidplatform; carriage means mounted in said track means for verticalmotion; said inner platform section being pivoted at its inner end tosaid carriage means about a horizontal axis; flexible supporting meansconnected between said carriage means and said outer platform formaintaining both said platform sections horizontal during load liftingand lowering operations and said platform, carriage means, and flexiblemeans movable vertically in unison as a rigid lift; and means forcollapsing said platform by providing an upward, vertical folding forceat said hinged connection, so that as the outer end of said innerplatform section is raised relative to the inner end of said innerplatform the underside of said outer platform section becomes faced withthe underside of said inner platform section so that when said platformis completely folded the two platform sections are vertically extendingand parallel to each other.
 2. The combination of claim 1 wherein saidtrack means extend above the bed of the truck and include a verticallyextending slot providing for attachment of the flexible support meanswith the carriage means above the hinged platform whereby the flexiblesupport means moves in said slot during raising and lowering of theplatform.
 3. The combination of claim 1 wherein said flexible supportmeans comprise a pair of chains adapted to extend from the associatedcarriage means to the outer platform section.
 4. In combination with therear of a truck, a tailgate lift for loading cargo onto the truck bedand having a folding platform adapted to also function as a tailgate,said lift comprising: a lift mechanism including a hydraulic power unitwith a drive cylinder at the rear of the truck and extendingtransversely of the truck; a folding hinged platform with a cargosupport surface having an inner platform section joined to an outerplatform section with a hinged connection; track means for supportingsaid platform and adapted to guide said platform; carriage means mountedin said track means for vertical motion and said carriage means beingoperatively connected with said drive cylinder for selective raising andlowering of the hinged platform; said inner platform section beingpivoted at its inner end to said carriage means about a horizontal axis;flexible support means connected to said carriage means at a point abovesaid platform and extending downward to said hinged platform formaintaining both of said platform sections horizontal during loadlifting and lowering operations; and means for collapsing said platformby rotating the cargo support surface of the inner platform toward therear of the truck, wherein, as the outer platform section is folded intothe inner platform section the underside of said outer platform sectionbecomes faced with the underside of said inner platform section so thatwhen said platform is completely folded the two platform sections arevertically extending and parallel to each other.
 5. The combination ofclaim 4 wherein said track means extend vertically above and below thebed of the truck and are disposed at each side end of truck and have achannel shaped cross section providing a vertically extending slot. 6.The combination of claim 4 wherein said inner platform section and saidouter platform section include abutting portions extending in agenerally vertical direction when the hinged platform is in a horizontalposition, and further, said hinged connection being attached at theunderside of both the inner platform section and the outer platformsection to thereby dispose the abutting portions of each platformsection in a rotation limiting face to face relation when the hingedplatform is in a horizontal load receiving position.
 7. The combinationof claim 5 wherein said flexible support means comprise a pair of chainsextending downward from the associated carriage means through thevertically extending slot of the adjacent track means to support theouter platform.
 8. A platform-type lift adapted to be attached to therear of a truck having a deck for carrying cargo and also having a rearportion through which cargo may be loaded and unloaded from the deck,the improvement comprising: a lift mechanism positioned at the rearportion of said truck and having a hydraulic power unit with a drivecylinder extending transversely of the truck; a foldable hinged platformadapted to receive cargo for loading and unloading from said truck andsaid hinged platform including both an inner platform section and anouter platform section pivotally connected by hinged means; track meansfixedly attached to said truck at the transverse sides of the rearportion thereof, and adapted to guide said platform in its verticalmovement; carriage means mounted in said track means for verticalmovement therein and said carriage means being operatively connectedthrough flexible load transferring means with said drive cylinder forselective raising and lowering of the hinged platform; said innerplatform section being pivotally connected at its inner end to thecarriage means about a horizontal axis; flexible chain means extendingbetween the vertically movable carriage means and the hinged platformfor maintaining both of said platform sections horizontal during loadlifting and lowering operations; platform folding means adjacent thehinged means to exert an upward vertical force thereby providing forcollapsing, folding, rotation of the platform sections to a generallyvertical collapsed position whereby the underside of the outer platformsection becomes faced with the underside of the inner platform section.9. The truck lift of claim 8 wherein the platform folding means forcollapsing said platform sections includes a flexible member extendableto at least one stationary point above said platform on the rear of saidtruck, for urging the underside of said outer platform into a portionadjacent the underside of said inner platform section to thereby presentthe outer and inner platform sections in a folded position wherein thetwo platform sections are vertically extending and parallel to eachother.
 10. The truck lift of claim 8 wherein said track means extendvertically above and below the bed of the truck and are disposed at eachside end of truck and have a channel shaped cross section providing avertically extending slot.
 11. The truck lift of claim 9 wherein saidinner platform section and said outer platform section include abuttingportions extending in a generally vertical direction when the hingedplatform is in a horizontal position, and further, said hingedconnection being attached at the underside of both the inner platformsection and the outer platform section to thereby dispose the abuttingportions of each platform section in a rotation limiting face to facerelation when the hinged platform is in a horizontal load receivingposition.